Category: marine and aquatic life

Readers’ wildlife photos

March 29, 2026 • 8:15 am

Abby Thompson of UC Davis has sent in some pictures of California tidepool organisms, as well as a video. Abby’s captions are indented and you can enlarge her photos by clicking on them.

Late January-early March tidepools, plus an octopus.

Bryozoans:

Lepas anatifera (pelagic gooseneck barnacle).   Usually found clinging to something drifting around in the open ocean (the “pelagic” part of their name), these were on a large log washed up on shore:

Intertidal zones, illustrated.    A well-placed vertical rock face, like this one, exhibits the idea of the different intertidal “zones”, each of which has its own specific collection of inhabitants.  You can see mussels and barnacles clustered at the top (in the “high intertidal”), exposed to the air as soon as the tide goes out even a little. There are smaller colonial anemones next, beneath them the orange and purple ochre stars, and below those, arriving at the low intertidal level, some giant green anemones.   If you peer into the water under the open giant green anemone, you’ll see a crab, probably a rock crab.   There’s some back and forth- there are a few giant green anemones pretty high up in this photo- but the general idea holds.

This reflects each animal’s differing tolerance for specific conditions- time out of the water as the tide goes out, harshness of wave actions, etc.      The nudibranchs (next few pictures) are usually in the very low intertidal:

Orienthella piunca (nudibranch):

Hermissenda opalescens (nudibranch):

Doto amyra (nudibranch).  Visible through the translucent skin on its back are lobules of the “ovotestis” (thanks inaturalist expert! ).   From google AI: “Ovotestes in nudibranchs are specialized, hermaphroditic reproductive glands that produce both male (sperm) and female (oocytes/eggs) gametes simultaneously”:

More eggs, this time from a snail in the genus Amphissa. I like the pointy egg casings, like wizards’ hats:

And here’s an adult of the genus- almost certainly Amphissa versicolor, but it’s an unusual color (they’re usually shades of orange or brown/tan):

In honor of Ghost the octopus, and also because I’ve finally figured out how to include videos, below is a clip from 2021 of an East Pacific red octopus (Octopus rubescens), cruising around the rocks (out of the water!) at low tide.  I’ve only seen one twice, probably because they’re too cleverly camouflaged (possibly just too clever) for me to spot.    This guy was about the size of a human hand, a miniature compared to the 50 pound Ghost.

Point Reyes peninsula at sunset:

Camera: Olympus TG-7.

Readers’ wildlife photos

March 23, 2026 • 8:15 am

Send ’em in if you got ’em.  The photo situation is dire.

But today we have whale photos by reader Ephriam Heller. His captions and IDs are indented, and you can enlarge his photos by clicking on them.

The best whale watching I have experienced is observing gray whales (Eschrichtius robustus) in the San Ignacio Lagoon on the Pacific coast of the Baja peninsula in Mexico. These whales are curious and “friendly,” often swimming up to boats to observe their occupants and even allowing themselves to be touched. Here is an example of an interaction between two species that each appear to exhibit curiosity and intelligence:

This is what a gray whale looks like (Image courtesy of International Whaling Commission):

They engage in numerous photogenic behaviors, such as rolling, riding the surf, waving their flippers and flukes in the air, and spyhopping to observe their surroundings.

The gray whale has longitudinal double blowholes. People claim that they form a heart shape, but think a heart with this shape needs immediate treatment:

When the sunlight hits their spray just right, one sees “rainblows”:

The gray whale has the most parasites of any whale, carrying up to 180 kg. At birth, babies have no barnacles or sea lice, but quickly acquire them from their mothers. The older the whale, the more barnacles and lice they collect. The whales rub along the seabed and piers to try to rid themselves of the parasites.

The whales carry one species of barnacle and four species of whale lice. The barnacles are Cryptolepas rhachianecti (whale barnacles) which are specific to gray whale hosts (i.e., they rarely occur on any other species), and they die when the whale dies.

There are four species of “whale lice,” which are not true lice (which are insects) but are amphipods in family Cyamidae: Cyamus scammony (the most common), Cyamus kessleri, and Cyamus eschrichtii are all found only on gray whales. Cyamus ceti is found on gray and bowhead whales. These cause minor irritation to healthy whales. Researchers view cyamid coverage and distribution (e.g., heavy clusters near blowhole, mouthline, genital slit) as indicators of stress, nutritional status, and chronic skin disease rather than as a primary cause of these problems.

There are two populations. The larger Eastern North Pacific population migrates along the continental coast between its breeding grounds in Baja, Mexico and its feeding grounds in Alaska. The small Western North Pacific population migrates along the Pacific coast of Asia. Gray whales hold the record for the longest migration of any mammal, with typical round-trip distances of about 20,000 km annually (although this isn’t close to the 70,000 km migration of the arctic tern).

Whales fall into two suborders: baleen (Mysticeti) and toothed (Odontoceti). Gray whales are in Mysticeti and use their baleen to feed on amphipods and plankton on the seafloor. During the six month summer feeding season, adults consume over 1 ton of food per day. They then fast for the remainder of the year, including the migration and winter birthing / breeding season. They exhibit “handedness,” in that most gray whales feed by scooping up sediments from the seafloor with the right side of their heads, resulting in their right sides having fewer adhering barnacles and sea lice.

They live up to ~70 years. Biggs transient killer whales (orcas) kill up to 35% of the calf population annually. Based on scarring, researchers speculate that almost every gray whale has been attacked by orcas. Most attacks occur as the young calves migrate north through Monterey Bay, California and Unimak Pass, Alaska.

The Eastern North Pacific population dropped to ~1,000 individuals around 1885 due to whaling, but has since recovered to ~27,000 in 2015-2016. The Western North Pacific population is tiny, comprising just a few hundred individuals. North Atlantic populations were extirpated (perhaps by whaling at the end of the medieval warm period) on the European coast in the 12th to 14th centuries, and on the American and African Atlantic coasts around the late 17th to early 18th centuries. Remains of gray whales from the time of the Roman empire have been found in the Mediterranean Sea, and they are still rarely seen there in modern times.

The gray whale has a dark slate-gray color and is covered by characteristic gray-white patterns, which are scars left by parasites that drop off in its cold feeding grounds. Individuals can be identified by their pigmentation patterns and their scars. I got this great photo of a whale’s tail; but it was just a fluke:

In case you are the kind of person who is interested in this sort of thing, this is what it looks like when whales mate:

Anyone with a younger brother will recognize this as the “head butt” greeting, a conserved behavior across all mammal species:

And this is the view when you saddle up a gray whale (I use a western saddle):

The eyes of gray whales are unlike the eyes of any other mammal I have seen, with what appear to be tangled filaments. My AI friend assures me that this is not the case and that they do not have any “extra” organs in their eyes: “The ‘tangled filaments’ you’re seeing are structures in the gray whale’s iris and surrounding tissues that become visible because the eye is small, very dark, and strongly three‑dimensional, so you are effectively looking across folded, ridged iris and ciliary tissues rather than through a flat, open pupil as in most mammals you see up close.”

Readers’ wildlife photos

March 13, 2026 • 8:15 am

Abby Thompson, a UC Davis mathematician, is back with more photos (and a video!) from the intertidal of northern California. Abby’s captions and IDs are indented, and you can enlarge her photos by clicking on them.

Jellyfish!

I thought I’d throw some jellyfish into the lull between the great winter tides and the great summer ones.

The reproductive cycles of the tidepool creatures are wildly varied, with behaviors ranging from maternal (see Epiactis prolifera from my last post), chancy (see mussels), through incessant (see nudibranchs).   But for sheer baroque complication, I vote for the jellyfish.    Many who stroll on a beach will see the quivering gelatinous masses of jellyfish stranded by the tide, and the less fortunate will have encountered their stinging tentacles while in the water.  This describes, a little, how they get there.

There are several jellyfish species common on the Northern California beaches; here are some of them:

Aurelia labiata (Greater Moon Jelly):

Chrysaora fuscescens (Pacific sea nettle):

Chrysaora colorata (purple-striped sea nettle) These are big, about a foot across:

Another Chrysaora colorata (handsome creatures):

Genus Aequorea (crystal jelly):

Polyorchis haplus:

Scrippsia pacifica (giant bell jelly):

The Chrysaoras and Aurelia labiata are in the class Scyphozoa; the rest are in the class Hydrozoa.

For all of these, males and females get together in the same vicinity, and release eggs and sperm (see “chancy” above), which form little “planulae”.    Then things get complicated.     Because (usually) the planulae settle down and attach themselves to something, and become polyps.  Like these tiny things:

Genus Sarsia:

Hydrocoryne bodegensis:

But how do they get from here (e.g. something like Sarsia) to there (e.g. something like Polyorchis haplus)?   Well they don’t, always, and sometimes they don’t get from there to here, either, but here’s an illustration of the process when it goes through a “typical” complete cycle:

And in fact if you look closely at that photo of H. bodegensis, you can see a little medusa just budding off, circled in the photo below:

Here’s a video of a set of newly-formed “baby jellyfish” (they look excited) which swam into my microscope view.    I didn’t know what I was seeing, so don’t have a photo of the polyp from which they likely emerged.   This means I have no idea of the genus (or even the class- if these are Scyphozoa then these are really ephyrae which will turn into medusae).

There seem to be many species for which the complete reproductive  process is not documented –  for example, if you search for the polyp stage of Polyorchis haplus, the answer is that we don’t know what it is, nor where it can be found.

 

A final oddity of this elaborate reproductive process is the existence of the so-called “immortal” jellyfish. (not found in the cold waters of Northern California).  If damaged at the medusa phase, this one can revert to its earlier (genetically identical) polyp phase- and so on ad infinitum, apparently.  As though, when things go wrong in your life, you could go back to your childhood and try again.

I’m grateful for help with IDs from experts on inaturalist and elsewhere.    All mistakes are mine.

Readers’ wildlife photos

March 12, 2026 • 8:15 am

And we have more photos. Today’s come from Jan Malik, documenting the birds of Barnegut Inlet in New Jersey. Jan’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

My previous batch from the Barnegat Inlet covered geese and ducks. It’s time for some of the other coastal birds now.

Immature Double-crested Cormorant (Nannopterum auritum). In contrast to diving ducks, these birds have no buoyancy problem and submerge easily.

Common Loon (Gavia immer). Judging by the slightly pinkish gape at the base of its bill and the fuzzy transition between black and white, this is an immature bird that stays on coastal bay waters before maturing and returning to quiet inland lakes to breed:

Another loon, this one with a mangled crustacean that I suspect is an Atlantic blue crab (Callinectes sapidus). I wonder if a diving loon preferentially picks a freshly molted crab the way we select ripe fruit:

Not a great loon picture, but we can see enough of the prey’s fins to identify the fish as an Oyster Toadfish (Opsanus tau), a species in which males provide parental care to eggs and young. The fish was big and bony, so the loon struggled a bit to swallow it. That fish would be a terrible choice for performing the Fish Slapping Dance. For the loon, it would be preferable to swallow its catch underwater, because at the surface it may be stolen by gulls, who know where a bird has dived and circle above waiting for it to reappear:

A couple of Savannah Sparrows were hopping on the rocks. I suspect that this pale bird with very little yellow in its brow is an Ipswich Sparrow, a subspecies (Passerculus sandwichensis princeps) that breeds on the sand spit of Sable Island off Nova Scotia:

Three species of shorebirds are common in winter at the Barnegat Inlet, all quite similar at first glance in size and plumage, but each occupying a different ecological niche. First, the Ruddy Turnstones (Arenaria interpres), here trying to sleep—probably using only one half of their brain to watch for predators, in unihemispheric slow-wave sleep. Their bills are short, stubby, and slightly upturned, adapted for—just as their name suggests—turning over beach debris to search for invertebrates hiding underneath:

Next, the Dunlins (Calidris alpina). They feed, roost, and migrate in large flocks. Unlike Turnstones, their bills are long, slender, and sensitive, used for probing tidal mudflats for worms and crustaceans:

Last, there are the Purple Sandpipers (Calidris maritima). Their bills are more “general purpose” than those of the other two species. Their covert feathers do show a purple sheen in the right light:

Purple Sandpipers and Dunlins are not very afraid of people on their wintering grounds; they may rest a few meters from a quiet observer. But the slightest hint of danger can trigger the whole flock to take flight in an instant—only to land nearby a moment later:

Purple Sandpipers are adapted to rocky coasts, where they feed on mussels exposed during low tides and on other invertebrates. The undersides of their feet must have a texture that allows them to walk sure‑footed on slime‑covered, slippery rocks:

 They have also evolved Silly Walks:

A distant Harbor Seal (Phoca vitulina), a frequent sight in the Inlet, always seems to look at the jetty with disappointment when it notices that this prime haul‑out spot is occupied by people:

As I was about to leave, the colors of the sunset behind a distant house caught my attention, so I took a picture, thinking little of it. Only back home—rather like the character in Antonioni’s Blowup—did I realize that the picture hides a predator the sleeping shorebirds must be on guard against. To be honest, I can’t be sure this was a flesh‑and‑blood predator and not one made of polystyrene, but the impression remains:

Readers’ wildlife photos

January 2, 2026 • 8:15 am

UC Davis Math professor (emerita) Abby Thompson sends some (mostly) intertidal photos, but from Hawaii rather than California. Abby’s captions are indented, and you can enlarge her photos by clicking on them.

We got to spend ten days before Koynezaa in Kauai, thereby missing some torrential northern California rains.    So here’s a little Hawaiian wildlife:

A not-great iphone photo:  This drama played out on our hotel walkway.  We came across a father explaining to his son that this was a momma snail taking care of her baby, a charming but inaccurate description.  In fact the “baby” is the voracious and carnivorous Rosy Wolfsnail (Euglandina rosea) which was introduced to combat the “momma” African Giant Snail (Lissachatina fulica), also an introduced species.  The result has been the extinction (by the wolfsnail) of some 8 species of endemic Hawaiian snails.  The Giant Snails (well, perhaps not this one in particular) are thriving.  The road to hell, etc.:

Cellana sandwicensis (yellow-foot ‘Ophi):

Arakawania granulata (Granulated drupe; [a gastropod]):

Actinopyga varians (Pacific white-spotted sea cucumber) Not the most attractive creature- and there are a lot of them.    They’re about 8” long and seem to just lie about.:

Colobocentrotus atratus (Shingle urchin). These very cool urchins make it look like a fleet of miniature spaceships have landed on the rocks:

Exaiptasia diaphana (pale anemone):

Gyractis sesere (colonial anemone):

Monetaria caputophidii (Hawaiin snakehead cowrie). Not sure where the snakehead part comes in:

Sunset behind the palm trees (iphone photo):

Most photos were with an Olympus TG-7, in microscope mode.

Readers’ wildlife photos

December 7, 2025 • 8:30 am

Today we have some marine mammal photos taken by Marcel van Oijen. Marcel’s captions are indented, and you can enlarge the photos by clicking on them.  Here’s a screenshot of the site, the island of Inchkeith:

Seal pup counting on the island of Inchkeith

Marcel van Oijen

The island of Inchkeith lies a few km from Scotland’s capital Edinburgh in the Firth of Forth, the sea-arm to the north. The last human to live on the island, the lighthouse-keeper, left in 1986. (The lighthouse is now controlled remotely from Edinburgh as are most lighthouses in Scotland.) Wildlife has since come back, and there is now a thriving colony of grey seals (Halichoerus grypus) producing around 900 pups each year. I took the photos below during the pup count of 29 November organised by the Forth Islands Heritage Group of volunteers.

This is near the harbour where we arrived, and we had to be careful not to get too close. Fortunately the female was busy keeping the male away from her pup. Cannibalism does happen occasionally.

Looking back to the harbour with the second group of volunteers just arriving. Note the many seals on the beach and in the water

Mating couple. The female life cycle is intense: a few weeks after giving birth and after the pup is weaned, they can be impregnated again:

This pup has moulted (i.e., lost its fluffy white baby-coat called the lanugo), so it will be three to four weeks old. At that age pups will be weaned and have to fend for themselves.

Two young pups who have just begun moulting, starting from the head:

Female seals carefully watching us:

This pup is nearly done moulting, some fluff left on top:

A moulted pup with an unusual colour, not the standard dappled grey:

Overview of ‘our’ patch of the island where we counted around 200 pups:

The most affectionate mother we saw on the island. She occasionally rolled on her back with eyes closed but always kept patting her pup with her front flipper:

Looking back to Inchkeith with fond memories!:

Readers’ wildlife photos

October 30, 2025 • 8:15 am

UC Davis math professor and Hero of Intellectual Freedom Abby Thompson sends us some intertidal photos (with one mammal). Abby’s IDs and captions are indented, and you can enlarge the photos by clicking on them.

And don’t forget to send in your photos!

A late summer entry from the tidepools, including a mystery through the microscope:

First, two handsome chitons:  these are the fellows who cling to rocks like a limpet, and, if dislodged, curl up like a pill-bug to protect their soft undersides:

(Lepidozona mertensii) Merton’s Chiton:

(Mopalia lignosa) Woody chiton:

Genus Themiste (peanut worm); the species is uncertain. The body of the worm lies below the sand.    The tentacles are very active (and very skittish), sweeping in particles towards the mouth:

I’ve posted some pictures of the deer that often come down to the beach before dawn.  The cliffs down to the beach are quite steep in places, and sadly sometimes the deer slip and fall.  This must have been a fawn (based on size).    Skip the next picture if you’re not a nature-tooth-and-claw person:

Dead deer- probably a mule deer, Odocoileus hemionus:

Diaulula odonoghuei (Northern leopard dorid):  This species is typically further north, although I’ve found it here a few times:

The next three photos are a puzzle to me, maybe some readers have a suggestion.   They’re through a microscope. I was looking at bryozoans on a piece of kelp, when I noticed some ring-like things on stems growing out of the bryozoans.    The first picture is a side view showing the stems.   In the second picture you can see the (greenish) rings forming inside one of the bryozoans- the rings seem to turn peachy as they mature.  The final picture shows the mature rings from above.   Inaturalist hasn’t come up with a suggestion so far.     From what I’ve read of marine bryozoans, I don’t think this is part of their reproductive cycle.    A tentative suggestion from the Bodega Marine Lab (thanks!!) is “stemmed diatoms”; the world is a mysterious place:

Triopha maculata– a particularly handsome nudibranch: